1. Field of the Invention
This invention generally relates to an improved track assembly that is installable around a standard, resilient tire, or over two tires in common mounted on dual or tandem wheels, in order to provide the tire greater flotation and mobility over soft and unimproved terrain. It is specifically concerned with an improved mechanism that facilitates the installation and removal of such tracks around such tires.
While numerous devices for improving the performance of vehicles having standard, resilient tires over soft or unimproved terrain are known in the prior art, the capabilities of such devices are quite limited. A particularly successful example of such a device is disclosed in U.S. Pat. No. 4,408,646 entitled "Wheeled Vehicle Support Apparatus" invented by Robert W. Forsyth, one of the co-inventors of the instant invention. Generally speaking, this particular support apparatus is an endless track of pivotally connected tread members that is installable around virtually any type of resilient tire whenever an improved performance over soft or unimproved terrain is desired. In contrast to prior art tracks, the support track disclosed in U.S. Pat. No. 4,408,646 utilizes tread members having a special geometry that significantly increases the surface contact area between the ground and the wheels of the vehicle bearing the tracks. This particular track exploits a lever action between centrally located or laterally disposed guide horns on the tread members that results in increased lengthwise contact between the wheels of the vehicle and the ground, which in turn maximizes flotation and reduces ground pressure, while minimizing sinkage and "bulldozing" resistance when the wheels and track are in motion.
Unfortunately, while the track disclosed in U.S. Pat. No. 4,408,646 substantially increases the ability of a conventional high-pressure tire on an aircraft, or on an armored personnel carrier, or on an artillery piece to negotiate soft soil or unimproved terrain, the particular design disclosed in the patent is not without limitations.
For example, it is difficult, if not impossible to install the track disclosed in this patent without the use of at least some standard hand tools. The necessity for the use of such hand tools creates delays in the installation of the track that can be problematical in circumstances where very rapid installation deployment of such tracks is necessary, such as when an attack on an airfield is imminent. Under such conditions, a rapid installation of a protective flotation track over the vulnerable, high-pressure tires of an aircraft would allow the aircraft to be very quickly towed off of the airfield and over the soft, unimproved ground that frequently surrounds such airfields, where it may be protectively camouflaged. Still another example of where such rapid installation is highly desirable would be where combat conditions necessitated the rapid movement of an artillery piece, supply truck or armored personnel carrier driven on conventional tires from a road to a marsh or snowfield. Under such circumstances, a delay of a few minutes in the installation of the tracks could have disastrous consequences.
A related limitation associated with the track disclosed in U.S. Pat. No. 4,408,646 is the fact that hand tools are also required to remove this track. Since the ground speed of the aircraft, armored personnel carrier or artillery piece is lessened by such tracks, it is highly desirable that they be quickly removed when the aircraft or other vehicle is returned to improved ground. Consequently, the delays associated with the removal of such tracks can create problems almost as serious as those discussed with respect to a delayed installation.
Still another limitation associated with prior art tracks is that their specific geometry renders it difficult to quickly render such tracks in a pattern that is both compact and mechanically stable. This limitation can pose a significant disadvantage in military applications, where storage space is a highly valuable commodity and mechanical stability is necessary to avoid movement and weight shifting, the latter being especially critical during air transport.
Clearly, there is a need for a protective flotation track that offers the flotation and mobility and protective advantages of prior art tracks but which is quickly and easily installable onto or removable from a particular tire. Ideally, such a track should be conveniently storable in a mechanically stable configuration when not in use so as to avoid movement and weight shifting during transport.